1. Field of the Invention
The present invention relates to a display device, and more particularly, to a thin and light autostereoscopic 3D display device that selectively switches between a 3D image mode and a 2D image mode.
2. Description of the Related Art
People perceive a three-dimensional effect because of physiological and psychological factors. In general, autostereoscopic 3D display techniques using binocular parallax, the largest factor in producing autostereoscopic viewing of an object at a short distance, permits people to achieve autostereoscopic viewing of an object. Techniques for displaying a 3D image are generally divided into those in which viewers wear a pair of eye-glasses and those in which viewers do not wear a pair of eye-glasses.
The techniques using eye-glasses can be classified into an anaglyph method in which the viewer wears a blue eye-glass and a red eye-glass for each of the viewer's eyes, a polarization method in which the viewer wears a pair of eye-glasses having lenses of different polarizations, and a time-sharing method in which periodically repeated time-shared polarization is synchronized with viewer eye-glasses having polarization shutters. However, wearing eye-glasses is inconvenient and makes it difficult for the viewer to observe other objects in addition to the 3D image.
Accordingly, research regarding the techniques in which the viewer does not wear eye-glasses has been actively conducted. The technique in which the viewer does not wear eye-glasses can be classified into a lenticular method in which a lenticular lens sheet using cylindrical lenses are perpendicularly arranged in front of a display panel and a parallax barrier method. With the development of a liquid crystal display device technique, a mechanical shutter can be substituted by a liquid crystal shutter, and accordingly, a 3D image and a 2D image can be selectively changed and used.
FIG. 1 is a view schematically illustrating an autostereoscopic 3D display device by a parallax barrier method that selectively switches between a 3D image and a 2D image.
As illustrated in FIG. 1, an autostereoscopic 3D display device 1 includes a backlight light source 40, a display panel 30, and a switching panel 20. The switching panel 20 includes an opaque slit unit, which becomes opaque with a predetermined width when an electric signal is supplied, and a transparent slit unit. The opaque slit unit and the transparent slit unit are alternately disposed.
An observer 10 views the display panel 30 through the transparent slit unit of the switching panel 20. The observer 10's left eye (L) sees a left eye region (Lp) of the display panel 30 through the transparent slit unit of the switching panel 20 and the observer 10's right eye sees a right eye region (Rp) of the display panel 30 through the transparent slit unit of the switching panel 20. In this manner, the observer 10's left eye (L) and right eye (R) see different regions of the display panel 30, respectively. The display panel 30 displays images corresponding to the observer 10's left eye and right eye in the left eye region (Lp) and the right eye region (Rp), respectively. Thus, the observer perceives a three-dimensional effect due to binocular parallax.
A structure of the switching panel 20 of the autostereoscopic 3D display device in accordance with the related art will now be described in detail with respect to FIG. 2.
As illustrated in FIG. 2, the switching panel 20 of the autostereoscopic 3D display device in the related art includes first and second transparent substrates 21 and 26 and a liquid crystal layer 25 formed between the first substrate 21 and the second substrate 26. Polarization plates 22 and 27 are attached to the outside of the first substrate 21 and the second substrate 26, respectively, a first electrode 23 formed of a transparent material such as ITO (indium tin oxide) is patterned and formed on the first substantial, and a second electrode 28 formed of the same material as the first electrode 23 is formed on an entire surface inside the second substrate 26. When electric signals are supplied to the first electrode 23 and the second electrode 28, liquid crystals between the first and second electrodes are driven to form the opaque slit unit.
Depending on whether or not the electric signals are supplied to the first electrode 23 and the second electrode 28, the display can be selectively switched between a 3D image mode and a 2D image mode. That is, when the signals are supplied to the first electrode 23 and the second electrode 28, a region where the first electrode 23 is formed makes the opaque slit unit, and therefore, the 3D image mode is implemented. When the signals are not supplied to the first electrode 23 and the second electrode 28, the 2D image mode is implemented.
However, when a liquid crystal display panel is used as the switching panel as described, the fabrication process becomes complicated since a process of fabricating the LCD panel and a process of mounting the fabricated LCD panel onto the polarization plate and the display panel are required. Thus, productivity is deteriorated. In addition, as the autostereoscopic 3D display increases in size due to the addition of the LCD panel, it is hard to obtain an autostereoscopic 3D display device that is thin and light weight. The addition of the LCD panel increases the unit cost of production and prevents mass production.